1、前言
kaptcha是一个非常实用的短信验证码生成工具，通过简单配置即可实现多样化的验证码。
2、引入依赖
<!--第三方验证码--><dependency> <groupId>com.github.penggle</groupId> <artifactId>kaptcha</artifactId> <version>2.3.2</version></dependency>
3、前台
假设前台调用样式如下：
<img alt="验证码" width="128" height="42" @click="changeImage" src="项目地址/validate/captcha-image" ref="checkCode"/>
通过调用 /validate/captcha-image 接口地址获取验证码。
4、后台
4.1 controller
@RequestMapping("/captcha-image")public void defaultKaptcha(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) throws Exception{ validateService.defaultKaptcha(httpServletRequest,httpServletResponse);}
4.2 serviceImpl
@Autowiredprivate StringRedisTemplate redisTemplate;@AutowiredDefaultKaptcha defaultKaptcha;//验证码失效时间 15分钟private static final int VALID_CODE_CACHE_EXPIRE_TIME = 900; /** * 生成图片验证码 * @param httpServletRequest request * @param httpServletResponse response */public void defaultKaptcha(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)throws Exception{ byte[] captchaChallengeAsJpeg = null; ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream(); try { /*生产验证码字符串并保存到session中*/ String createText = defaultKaptcha.createText(); String key = String.format("login_valid_code_%s", httpServletRequest.getSession().getId()); redisTemplate.opsForValue().set(key, createText, VALID_CODE_CACHE_EXPIRE_TIME, TimeUnit.SECONDS); //httpServletRequest.getSession().setAttribute("vrifyCode", createText); //使用生产的验证码字符串返回一个BufferedImage对象并转为byte写入到byte数组中 BufferedImage challenge = defaultKaptcha.createImage(createText); ImageIO.write(challenge, "jpg", jpegOutputStream); } catch (IllegalArgumentException e) { httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND); return; } //定义response输出类型为image/jpeg类型，使用response输出流输出图片的byte数组 captchaChallengeAsJpeg = jpegOutputStream.toByteArray(); httpServletResponse.setHeader("Cache-Control", "no-store"); httpServletResponse.setHeader("Pragma", "no-cache"); httpServletResponse.setDateHeader("Expires", 0); httpServletResponse.setContentType("image/jpeg"); ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream(); responseOutputStream.write(captchaChallengeAsJpeg); responseOutputStream.flush(); responseOutputStream.close();}
补充：DefaultKaptcha是引入kaptcha依赖后即直接可引入的;
如上思路代码已经很清晰了，通过DefaultKaptcha创建验证码文本，然后存入redis一份，用于后面的验证使用；
注意：redis 拼接的 key 规则为 login_valid_code_ + sessionId（session id）
5、效果
前端实际应用效果:
浏览器直接调用接口效果:
6、验证
6.1 controller
从redis中取
/** * 验证验证码 * @return Object */@UnAuthorization@RequestMapping(value = "code/check", method = {RequestMethod.POST})public Object checkCode(@RequestBody @Valid CheckValidateRequest checkValidateRequest , BindingResult bindingResult, HttpServletRequest request) { return validateService.checkValidateCode(httpServletRequest.getSession().getId(),checkValidateRequest.getValidCode());}
6.2 serviceImpl
/** * 验证短信验证码有效性 * @param mobile 手机号码 或者 sessionId * @param validCode 验证码 * @return boolean */public boolean checkValidateCode(String sessionId, String validCode) { Object iValidCodeFromRedis = cacheService.getCache(String.format("login_valid_code_%s", sessionId)); String sValidCodeFromRedis = String.valueOf(iValidCodeFromRedis); if (StringUtils.isNotBlank(sValidCodeFromRedis) && validCode.equalsIgnoreCase(sValidCodeFromRedis)) { return true; } throw new CommonException(ValidateStatusEn.CHECK_VALID_CODE_FAILED.getErrorMsg(), ValidateStatusEn.CHECK_VALID_CODE_FAILED.getErrorCode());}
补充：通过 login_valid_code_ + sessionId 从 redis 中获取验证码进行校验。
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